Hydrolysis of n-substituted amides



United States Patent HYDROLYSIS F N-SUBSTITUTED AMIDES William L. Moshy, North "Plainfield, and Saul R. Buc,

Easton, N.J., assignors toGenerzrl Aniline & Film CorporatiomNew York, N.Y., a corporation of Delaware No Drawing. Application July 2, 1956 Serial No. 595,139

7 Claims. (Cl-.260-515) This invention relates to the hydrolysis of N-substituted amides of acenaphthene carboxylic acids and relates-more particularly to the hydrolysis of acenaphthene 'carboxanilides to produce their corresponding acids.

Heretofore, in the hydrolysis of N-substituted amides of acenaphthene carboxylic acids the hydrolytic medium employed comprised ethylene glycol and potassium hydroxide. However, the results obtained by the use of this hydrolytic medium were not satisfactory as to yield or purity. The amount of final product obtained fell 1213% short of quantitative yield and was quite impure. It is, accordingly, an important object of this invention to provide a novel process for the hydrolysis of acenaphthene carboxanilides to their corresponding acids wherein improved yield and quality of product is obtained.

Another object of this invention is the provision of an improved process for hydrolyzing acenaphthene carboxanilides to their corresponding acids by the use of an aqueous hydrolytic medium containing a surface active agent and an excess of alkali.

Other objects of this invention will appear from the following detailed description and claims.

The process of the instant invention may be employed in the hydrolysis of any N-substituted amide of acenaphthene carboxylic acid. However, this invention will be particularly described in connection with the hydrolysis of acenaphthene S-carboxanilide and acenaphthene 5,6- carboxanilide to their corresponding acids, namely 5- acenaphthoic acid and 5,6-acenaphthalic acid, respectively, since these are valuable intermediates for dyestuffs, fluorescing agents and pharmaceuticals. For example, 5,6-acenaphthalic acid may be oxidized in substantially quantitative yield to 1,4,5,8-tetracarboxylic acid (Tetra Acid) which is useful in the preparation of vat dyes such as Indanthrene Brilliant Orange GR, Indanthrene Scarlet GG, Indanthrene Bordeaux RR and the like.

In accordance with this invention, the N-substituted amide, such as acenaphthene S-carboxanilide and acenaphthene 5,6-carboxanilide, are hydrolyzed by suspending the amide in water containing a slight excess of caustic and a trace of wetting agent or detergent, and the suspension heated under superatmospheric pressure for 4 to 6 hours at a temperature of about 200 C. The solution obtained is treated with a suitable acid, such as hydrochloric acid or sulfuric acid, for example, to produce the corresponding organic acid. If desired, a few steel balls may be added to the suspension for the purpose of breaking up any lumps therein and thus facilitating hydrolysis.

Any suitable alkaliand heat-stable wetting agent or detergent may be employed in the process of the instant invention such as, for example, the dioctyl ester of wifesuccinic acid (Aerosol OT), alkyl benzene sulfonates, e.g. dodecyl benzene sulfonates, Igepon T types (N-acyl- N-methyl-taurines), Igepal types (polyoxyethylated alkyl "ice phenols), long chain alcohol sulfates and Alipals (sulfated polyoxyethylated alkyl phenols).

The instant invention will be more clearly understood from the'following examples which are merely illustrative and inno way flimitative.

Example I drying gave a quantitative yield of pure white S-acenaphthoic acid.

Example II A mixture of 156 grams of acenaphthene 5,6-dicarbanilide, 58 grams of potassium hydroxide, 1 gram of Aerosol OT and 600 cc. of water, to which were added a few %-inch steel balls, was shaken in a steel bomb for 6 hours at 200 C. The dark-brown solution obtained was adjusted to approximately pH 7 With dilute hydrochloric acid, charcoaled and filtered. Acidification, filtering, washing and drying gave an almost quantitative yield of nearly white 5,6-acenaphthalic acid.

It is to be understood that the foregoing detailed description is given merely by way of illustration and that many variations may be made therein without departing from the spirit of our invention.

Having described our invention what we desire to secure by Letters Patent is:

1. Process for preparing acenaphthene carboxylic acids, which comprises suspending an N-substituted amide of acenaphthene carboxylic acid, selected from the group consisting of acenaphthene S-carboxanilide and acenaphthene 5,6-carboxanilide, in water containing an excess of caustic and a small amount of alkaliand heatstable detergent, heating said suspension at a temperature of about 200 C. for from four to six hours, and acidifying the resulting solution.

2. Process for preparing acenaphthene carboxylic acids, which comprises suspending an N-substituted amide of acenaphthene carboxylic acid, selected from the group consisting of acenaphthene 5- carboxanilide and acenaphthene 5,6-carboxanilide, in water containing an excess of caustic and a small amount of alkaliand heatstable detergent, heating said suspension at a temperature of about 200 C. for from four to six hours, and acidifying the resulting solution by adding thereto a mineral acid so as to cause acenaphthene carboxylic acid to precipitate.

3. Process for preparing acenaphthene carboxylic acids, which comprises suspending an N-substituted amide of acenaphthene carboxylic acid, selected from the group consisting of acenaphthene S-carboxanilide and acenaphthene 5,6-carboxanilide, in water containing an excess of caustic, selected from the group consisting of sodium hydroxide and potassium hydroxide, and a small amount of alkaliand heat-stable detergent, heating said suspension at a temperature of about 200 C. for from four to six hours, and acidifying the resulting solution by adding thereto a mineral acid so as to cause acenaphthene carboxylic acid to precipitate.

4. Process for preparing S-acenaphthoic acid, which comprises forming a mixture of acenaphthene S-carboxanilide, an excess of sodium hydroxide, a small amount of alkaliand heat-stable detergent and water, heating said mixture under pressure and with agitation for 4 hours at 200 C., and precipitating S-acenaphthoic acid from the resulting solution by adding hydrochloric acid to said solution.

5. Process for preparing 5,6-acenaphthalic acid, which comprises forming a mixture of acenaphthene 5,6-dicarboxanilide, an excess of potassium hydroxide, a small amount of alkaliand heat-stable detergent and water, heating said mixture under pressure and with agitation for 6 hours at 200 C., and precipitating 5,6-acenaphthalic acid from the resulting solution by adding hydrochloric acid to said solution.

6. Process for preparing S-acenaphthoic acid, which comprises forming a mixture of acenaphthene S-carboxanilide, an excess of sodium hydroxide, a small amount of alkaliand heat-stable detergent and water, heating said mixture under pressure and with agitation in the presence of steel balls for 4 hours at 200 C., and precipitating S-acenaphthoic acid from the resulting solution by adding hydrochloric acid to said solution.

7. Process for preparing 5,6-acenaphthalic acid, which References Cited in the file of this patent UNITED STATES P TENTS 2,498,656 De Groote et al. Feb. 28, 1950 2,509,245 Nikawitz et a1 May 30, 1950 FOREIGN PATENTS 274,894 Great Britain Feb. 16, 1928 783,091 France July 8, 1935 OTHER REFERENCES Schwartz et 211.: Surface Active Agents, pp. 380, 513-514 (1949), Interscience Publishers. 

1. PROCESS FOR PREPARING ACENAPHTHENE CARBOXYLIC ACIDS, WHICH COMPRISES SUSPENDING AN N-SUBSTITUTED AMIDE OF ACENAPHTHENE CARBOXYLIC ACID, SELECTED FROM THE GROUP CONSISTING OF ACENAPHTHENE 5-CARBOXANILIDE AND ACENAPHTHENE 5,6-CARBOXANILIDE, IN WATER CONTAINING AN EXCESS OF CAUSTIC AND A SMALL AMOUNT OF ALKALI- AND HEATSTABLE DETERGENT, HEATING SAID SUSPENSION AT A TEMPERATURE OF ABOUT 200*C, FOR FROM FOUR TO SIX HOURS, AND ACIDIFYING THE RESULTING SOLUTION. 